In, for example, the manufacture of seat cushions, impervious material, which is impervious to the passage of foam material and air, is placed over a mould and is held by a slip ring at the periphery of the mould. Excess material extends beyond the slip ring and, when the process is carried out and the vacuum draws the material into the mould, some of the excess material is drawn past the slip ring. As is apparent, the pressure of the slip ring on the material controls the amount of material that passes into the mould. With greater pressure applied by the slip ring to hold the material, more of the material is stretched as the vacuum is applied and stretched material is drawn into the mould to conform to the inner surface of the mould. However, thin spots may result. On the other hand, if the slip ring exerts less pressure, then more material may enter into the mould to conform to the inner surface of the mould. However, wrinkles will then occur in the material.
A further difficult with the procedure is that the process of positioning each piece of material in the mould is operator dependent. With respect to each piece of material, the operator must use his or her judgment to ensure that sufficient material is drawn into the mould with sufficient stretching so that there are no wrinkles in the material in the mould and no thin spots prior to the closing of the mould land injecting for example, polyurethane foam material into the mould which adheres to the material forming the interior of the finished product. The operator must then repeat this same process with each operation to achieve a finished product which will be slightly different from the next.
Furthermore, after for example a seat bottom or cushion for a vehicle has been moulded, excess material must be removed. Thereafter, mounting skirts are sewn or secured ont he edges of the seat cushion. In most instances, the material used is stretchy, as, for example, Lycra, being tightly woven so the material can stretch. However, such material is costly.
It is therefore an object of this invention to provide improved products and improved processes for manufacturing such products.
It is a further object of this invention to reduce the set-up time for the moulding of such products.
It is a further object of the invention to reduce the costs of manufacturing such products.
It is a further object of the invention to produce such products with less costly materials.
It is a further object of the invention to provide improved components and equipment suitable for use in such processes.
It is still a further object of this invention to provide some improved components and equipment which are made up of less parts than the equipment they replace.
Further and other objects of the invention will be realized by those skilled in the art by the following summary of the invention and detailed description of the embodiments thereof.